Implantable devices exist that electrically stimulate body tissue to treat or relieve the symptoms of a wide variety of physiological or psychological maladies. Such devices are typically part of systems that are entirely implantable within the patient or are partially implantable and partially external to the patient. Systems that are entirely implantable in the patient typically include an implantable medical device some of which may have medical leads for sensing and therapy delivery functions. In such a system, the implantable medical device is entirely implanted in the bodies of the patients.
Such implantable devices are often powered by an internal power source, such as a battery, to power the device functions continuously over a long period of time. Often for implantable medical devices, the power source used to power the device's circuitry is non-rechargeable. The power source is included in the implantable device, which in turn is surgically implanted and is typically intended to be physically inaccessible. As such, the longevity of the device is a function of the rate of depletion of the battery, which may range from approximately three (3) years to approximately eight (8) years based upon the usage of the stored charge.
There remains a need for techniques to optimize the consumption of the charge stored by the power source to extend the device longevity.